Toss bread with ham, tomato, cheese and green onion. Transfer to a microwave-safe mug. Whisk egg with milk; pour over filling.
Microwave on High (100%) for 60 seconds; let stand for 10 seconds. Microwave on High (100%) for an additional 60 seconds or until set.
Use any of your favourite meat, veggies, and cheese to have a different breakfast each morning.